Knowledge Bank

The $\nu 2$ bending fundamental of the formyl radical HCO $(\nu 0=1080.76$ $cm-1$) has been studied by the technique of laser Zeeman spectroscopy (``laser magnetic resonance”). Fluorine atoms from a discharge in $CF4$ were reacted with $H2CO$ to form the HCO, which flowed through an absorption cell located between the pole faces of an electromagnet and within the optical cavity of a $CO2$ laser. The present work extends the earlier $study1$ of this band, in our laboratory, by $CO2$ laser Stark spectroscopy. Over 100 Zeeman resonances involving levels with $J\le 7$ and $Ka\le 3$ have been detected and assigned, enabling accurate determinations of the band origin and the excited state rotational, centrifugal distortion, and spin rotation interaction parameters to be made. There are fairly large changes in the values of A, $\Delta kϵaa$, and $\pi K$ between the ground and $v2=1$ states.